Various types of air-filled supports for vehicle seating surfaces have been developed. Depending on the particular configuration and in the intended pressurization scheme to be employed, varying routing and control networks for the air-to be distributed among the various bladders can differ. In various examples, such routing may be achieved by forming capillaries or other air supply lines into the bladder network along with bladder formation, which may be carried out using, for example, a dual hot plate vacuum forming process. Such a process, however, is largely inflexible, requiring separate molds for each routing pattern, even among a common bladder network. Alternatively, various individual capillaries can be positioned between sheets during bladder unit formation. This process can be time-consuming and expensive and can result in high failure rates due to the delicate nature of the capillaries and the accuracy with which they must be placed to achieve a proper seal of the associated cells.